Periodic Properties of Atoms and Ions

Question 1

How can periodic trends be predicted?

Answer 1

using electron density distribution; electron repulsion

Question 2

Effective nuclear charge (Zeff)

Answer 2

the positive nuclear charge (given by atomic number) reduced by the repulsion of a specific electron by all the other electrons; increases left to right; nuclear charge felt by an electron after considering electron screening

Question 3

Atomic radius trend

Answer 3

increases down a group, decreases left to right

Question 3

Ionization energy

Answer 3

minimum energy required to remove an electron from an atomic orbital it occupies

Question 4

First ionization energy

Answer 4

the amount of energy needed to remove the least tightly bound electron

Question 5

Ionization energy trends

Answer 5

increases left to right and decreases top to bottom; higher energy orbital = lower IE; lower Zeff = lower IE; if subshells are more than half filled IE are lower than expected because of electron repulsions

Question 6

Electron affinity

Answer 6

the change in energy when an electron is added to an atom to form an anion; more stable as anion if EA<0 and opposite for cation

Question 7

Ionic radius

Answer 7

Radius of an ion (sphere)